ATA555812-DDT

Features • • • • • • • • • Contactless Read/Write Data Transmission Radio Frequency fRF: 100 kHz to 200 kHz User Memory (1024 Bits): 32 Write Protectable 32-bit Blocks of Data Deterministic Anticollision: Detection Rate ~ 20 Tags/s with 40-bit Tag ID, RF/32 On-chip CRC Generator: 16-bit CRC-CCITT Compliant to ISO/IEC 11785 Downlink Transmission: Enhanced 1 out of 4 Pulse Interval Encoding (~ 5 kbps) Uplink Transmission: ASK Modulated, NRZ, Manchester or Bi-phase Encoding Integrated Tuning Capacitor: 75 pF ±10% as Mask Option System Memory (320 bits): – 10 Write and Password Protectable 32 Bit Blocks of Data – Tag ID (96 Bits Maximum) – Traceability Data with Inherent Manufacturer Serial Number – Write Password (32 Bits) and Read Password (32 Bits), with Page Orientated Memory Protection Areas – Configuration Register for Setup of: • Selectable Data Bit Rate: RF/2 .. RF/64 • Selectable Tag ID Length to Optimize Anticollision Detection Rate • Start of Frame with Variable Preamble Length to Simplify Interrogator Design • Public Mode (PM) for Read Only Tag Emulation • Electrical Article Surveillance (EAS) Mode • Direct Data (NRZ), Bi-phase (FDX-B) or Manchester Data Encoding 1 kbit R/W IDIC® with Deterministic Anticollision ATA5558 Preliminary 1. General Description The ATA5558 is a contactless, two-terminal R/W-Identification IC (IDIC®) for multi- or single tag applications in the low frequency (≈ 125 kHz) range. The passive tag uses the external RF signal to generate it’s own power supply and internal clock reference. Figure 1-1. RFID System Using an ATA5558 Tag Transponder Coil interface Power Reader or Base station Interrogator Data Controller * Memory ATA5558 * Mask option It contains an EEPROM which is subdivided into 1024 bits of user memory and 320 bits of system memory. Both memory sections are organized in data blocks of 32 bits, each equipped with an associated lock bit for block write protection. The user memory, which is intended for storage of recallable user data, is made of 32 such blocks. The 10 block system memory section is reserved for system parameter and configuration settings. Two of these blocks include a 32 bit read and a 32 bit write password to prevent unauthorized read and/or write access to protected user definable memory pages. Rev. 4681C–RFID–09/05 The ATA5558 receives commands from the interrogator (downlink) as a 1 out of 4 pulse interval encoded, amplitude modulated signal. Return data transmission from the tag to the interrogator (uplink) utilizes either Manchester, Bi-phase or NRZ encoded amplitude modulation. This is achieved by controlled damping of the interrogator’s RF field with an on-chip resistive load between the two tag terminals, Coil 1 and Coil 2. Multi-Tag identification is implemented using a deterministic anticollision algorithm which requires unique tag identification information (Tag ID’s). Three blocks within the system memory are reserved for storage of the Tag ID, the length of which is user configurable up to a maximum of 96 bits. Figure 1-2. System Block Diagram Modulator System memory PPM signal Binary bitrate decoder generator Analog front end Coil 1 Mode register User memory (1kbit EEPROM) Controller Input register Anticollision logic Coil 2 POR * HV generator * mask option 2. Functional Blocks 2.1 Analog Front End The analog front end (AFE) includes all circuitry directly associated with the coil interface. It generates the internal power supply and handles the data communication with the interrogator. It consists of the following blocks: • Rectifier to generate a DC supply voltage from the AC coil voltage • Low-voltage regulator to provide an on-chip stabilized DC voltage • Charge pump to generate the high voltage required for EEPROM programming • On-chip tuning capacitor (mask option) • Field clock extractor • Field gap detector for data transmission from interrogator to tag • Load switching between Coil 1/Coil 2 for data transmission from tag to interrogator • Electrostatic discharge protection (ESD) 2 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] 2.2 Power-On Reset (POR) and Initialization The Power-On-Reset circuit (POR) maintains the circuit in a reset state until an adequate internal operating voltage threshold level has been reached, whereupon a default start-up delay sequence is started. During this period of 200 field clock cycles, the configuration and security setup is initialized from the System Configuration and Page Security blocks. 2.3 Control Logic The control logic is responsible for the following functions: • Initialization and reloading of the configuration from EEPROM • Control of read and write memory access operations • Data transmission and command decoding • CRC check, error detection and error handling 2.4 Modulator The modulator output circuitry controls the switching of a resistive load between the Coil 1 and Coil 2 pads to transmit data from the tag to the interrogator (uplink). The ASK load modulator is driven from the Manchester, Bi-phase encoder or directly from the EEPROM memory data stream (NRZ) according to the uplink encoding configuration. Table 2-1. Uplink Mode Types of Modulation Manchester Encoding Bi-phase Encoding(1) NRZ – Direct Data ASK-coded 0 = falling edge on mid bit 0 = rising or falling edge 1 = modulation off modulation 1 = rising edge on mid bit 1 = no edge on mid bit 0 = modulation on Note: 1. Since Bi-phase encoding is data dependent the following definitions apply to the ATA5558 implementation. - The tag modulates the first (half) bit period after SOF. - If the last bit of a data stream is a logical 1 it is possible that this bit period is non-modulated and therefore is not detectable directly by the reader. Figure 2-1. Manchester Timing Diagram 1 Data rate = FRF/16 0 0 1 NRZ data stream Manchester coded Modulator signal Manchester coded RF field 3 4681C–RFID–09/05 Figure 2-2. Bi-phase Timing Diagram 1 0 Data rate = FRF/8 0 1 1 1 0 1 NRZ data stream Biphase coded RF field Bi-phase coded Modulator signal 2.5 Binary Bit Rate Generator The tag’s data rate is binary programmable in the configuration register to operate at any bit rate between RF/2 and RF/64. RF Data rate = -------------------2(n + 1) 2.6 2.6.1 Memory Section Memory Map The physical memory is subdivided into two logical sections (see Figure 2-3). The first logical memory section contains the 1024 bits of user data. The second logical memory section contains 320 bits of system/configuration data. Both memories are organized in 32-bit data blocks, each block being equipped with a single lock bit, with which the associated block can be write protected. Command controlled programming and reading always takes place on a serial MSB first block basis so that a block constitutes the smallest directly accessible data unit. The user memory is further subdivided into 8 pages, each of 4 blocks in size. This provides the basis of the page security scheme (“Password Protection” on page 6). Figure 2-3. Memory Map Structure User memory 31 30 31 29 28 27 : 7 6 5 4 3 2 1 0 L L L L L : L L L L L L L L User data block31/page7 User data block30/page7 User data block29/page7 User data block28/page7 User data block27/page6 1Fh 1Eh 1Dh 1Ch 1Bh 07h 06h 05h 04h 03h 02h 01h 00h 1 0 System memory : User data block7/page1 User data block6/page1 User data block5/page1 User data block4/page1 User data block3/page0 User data block2/page0 User data block1/page0 User data block0/page0 bit position 2 63 62 61 60 59 58 57 56 55 54 L L L L L L L L L L Configuration Password/Page Security Traceability 3 Traceability 2 Traceability 1 Tag ID 3 Tag ID 2 Tag ID 1 Password - Write Password - Read bit position 2 1 0 3Fh 3Eh 3Dh 3Ch 3Bh 3Ah 39h 38h 37h 36h L 31 30 29 L 31 30 29 Lock bits 4 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] A valid Write command can be used for programming a data block of 33 bits – including the associated lock bit – into an addressed location of either memory section. Once locked (lock bit = 1), the entire block including the lock bit itself can no longer be reprogrammed selectively. The system memory section is situated at the upper end of the (6-bit) memory address range and contains all system parameters and configuration settings. This area has restricted access (see Figure 2-5 on page 7) and the majority of blocks can only be read or written after the successful execution of the appropriate Password Login command (see Table 7-1 on page 24). All the configuration settings are allocated in block 63 (see Figure 2-7 on page 9) and the password protection security information in block 62 (see Figure 2-6 on page 7). 2.6.2 Traceability Data The traceability information is programmed and locked into the traceability blocks (59-61) by Atmel during the production test. Figure 2-4. Tag ID and Traceability Structure Traceability 31 ................................. 16 Block 61 Block 60 Block 59 31 30 .............. 26 RFU 15 ......... 8 ACL 7 ............. 0 MFC ICR LotID IC code wafer # 5bit die on wafer 18 bit LotID 25 ........................ 8 TagID 7... 4 3 ... 0 Block 58 Block 57 Block 56 TagID(msb-64).......TagID(msb-79) TagID(msb-32).......TagID(msb-48) TagID(msb)...........TagID(msb-16) TagID(msb-80)........TagID(msb-95) TagID(msb-49)........TagID(msb-63) TagID(msb-17)........TagID(msb-31) 31 ................... 16 15 ..................... 0 Anticollison detection starts with this bit IC code ACL MFC ICR DPW Wafer# Lot ID RFU 4-digit Atmel IC reference number, e.g. ’5558’ Allocation class as defined in ISO/IEC TDR 15963-1 = E0h Manufacturer code of Atmel Corp. as defined in ISO/IEC 7816-6/AM1 = 15h 4-bit Atmel IC revision code 18-bit binary encoded die on wafer 5-bit binary wafer number 9-digit lot number Reserved for Future Use 5 4681C–RFID–09/05 The blocks 59, 60 and 61 contain Atmel’s manufacturer’s serial number (MSN). The top 4 digits of block 61 specifiy the IC code of this product. The following byte of block 61 is fixed to E0h which is the allocation class (ACL) for registered IC manufacturers as defined in TDR 15963-1; followed by the manufacturer code (MFC), which compliant with ISO/IEC 7816-6/AM1, is defined as 15h for Atmel. The remaining two blocks contain a 64-bit Atmel unique traceability code. The data is divided in several sub-groups, a 36-bit lot ID code, a 5-bit wafer number and a 18-bit sequential die number which represents the physical location of the chip on the processed wafer. The ICR nibble (4 bits) of this manufacturer serial number (MSN) is used for the IC reference/version (ICR). The unique tag identifier (Tag ID) blocks provide an address code with which each tag can be individually identified and interrogated. These codes are programmed by either the tag system administrator or the tag manufacturer into blocks 56 to 58. The allocation of individual Identification codes must be handled so that an interrogator can never be confronted with two tags with identical Tag IDs. This is an important issue as the Tag ID is used as the basis for accessing and sorting tags during anticollision commands GetID, Select and SelectGroup. The Atmel traceability code (blocks 60 and 59) itself provides a means of unique chip identification so that this data content can be used as the Tag ID or a part of the Tag ID by copying it or part of it into blocks 56 and 57. The Tag ID code is located in blocks 56 to 58. It is MSB aligned so that it may occupy between 16 and 96 bits (see Figure 2-4 on page 5). This Tag ID length is set in the configuration block (see Figure 2-7 on page 9) and has an impact on the time required to complete the anticollision detection loop so it should be adjusted to suit system requirements. The default preprogrammed Tag ID length is 64 bits. The anticollision algorithm is based on a bit by bit binary tree elimination, carried out in parallel on all the Tag IDs within the interrogator field. This starts with the MSB of the Tag ID (always in bit position 31 of block 56) and continues through to bit position 0 of block 58 or until the Tag ID LSB, indicated by the configuration Tag ID length, is reached. 2.7 Security Levels The ATA5558 has three levels of security. Firstly, the restricted password access which prevents unauthorized access to both user and system data but allows authorized access using the correct password. Then a block orientated absolute write lock protection (lock bits) and finally the Master Key with a security code which has to be set in the configuration block accordingly (see Table 2-2 on page 8 and Figure 2-7 on page 9). 2.7.1 Password Protection The user memory is subdivided into continuous page areas which can be configured so that write or read/write and write operations on blocks within these pages can only be carried out after the appropriate password has been transmitted to the tag (LoginRead or LoginWrite command). The read and write password protections are independent and user definable. The read and write passwords are found in blocks 54 and 55 and the page security levels are defined in the Page Security register of block 62 (see Figure 2-6 on page 7). 6 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] To access a protected memory block, a Login command with the corresponding read or write password had to be executed once per session. During the login procedure the 32-bit password field of the login command is compared with the contents of the corresponding password in the system memory. If the passwords match, the ATA5558 tag will return an SOF pattern as an acknowledge signal. If they do not match, the tag will respond with an SOF followed by the appropriate error code. Writing to a protected memory address which has not been enabled with the correct LoginWrite password, will result in an error code on completion of the interrogator command. Reading a password protected memory address which has not been enabled with the correct LoginRead password, returns a block of all 0 data and no error code. Figure 2-5. System Memory Access Read Access Configuration Page Security Traceability 3 Traceability 2 Traceability 1 Tag ID 3 Tag ID 2 Tag ID 1 Password - Write Password - Read 63 62 61 60 59 58 57 56 55 54 Write Access Configuration Page Security Traceability 3 Traceability 2 Traceability 1 Tag ID 3 Tag ID 2 Tag ID 1 Password - Write Password - Read Block Name Unlimited Access Block Name Password Access Block Name No Access Figure 2-6. Page Security Register MSB............. ...........LSB L 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 P7a P7b P6a P6b P5a P5b P4a P4b P3a P3b P2a P2b P1a P1b P0a P0b reserved Code Pxa Pxb 0 0 1 0 0 1 1 1 Password required for write read no no yes no yes yes reserved reserved Page 7 Page 6 Page 5 Page 4 Page Security Data Page 0 Page 1 Page 2 Page 3 2.7.2 Lock Bit Each memory block, consists of 32 data bits and an associated lock bit (see Figure 2-3 on page 4). Once a block is locked (lock bit = 1), the entire block including the lock bit itself can no longer be reprogrammed 7 4681C–RFID–09/05 2.7.3 Master Key The Master Key controls various operating modes as described in Table 2-2. For production test purposes, other Master Key codes are used, but once the Configuration block has been double locked these test functions can never be reactivated. If the Master Key is set to 0110, the blocks within the system memory section have different access protection (see Figure 2-5 on page 7). These access rights are fixed and not influenced by the Page Security Register. Access to password protected system memory blocks can only be performed after the corresponding LoginWrite or LoginRead has been successfully executed. The password blocks themselves are non-readable. Traceability and configuration can always be read but the traceability data cannot be altered. Table 2-2. Master Key Related Functions Enables Protection Scheme User Memory Clear no yes yes Page Security yes yes no System Memory yes yes no Master Key 6 9 others DDR yes yes no PM yes yes no EAS yes yes no A new ATA5558 device, when received by the customer can be considered as being unprogrammed (all 0 s tate), the only exception to this being the preprogrammed non-alterable traceability information. For the tag manufacturer to be able to easily set up the tag passwords, it is possible to provisionally switch the password protection off. i.e Master Key = 0. In this state, it is possible to read and write all non-locked (lock bits = 0) memory blocks irrespective of the page security. In this way, new tag passwords or Tag ID’s can be defined and written. Blocks, which have once been locked (block lock bit = 1) can however not be rewritten. When the customer has completed the tag configuration, the Master Key is set to the “safe” state (= 6) thus enabling the full password protection, and then finally the configuration block itself may be locked. In this double locked condition, the configuration and all other locked blocks are irreversibly set and cannot be changed. This applies to both the user and the majority of the system memory blocks. 8 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] 2.8 Tag Configuration Register The internal tag configuration register holds a shadow copy of the configuration settings stored in the system memory’s block 63. It is refreshed after every POR cycle (RF field on), Reset to Ready or Write to block 63. Figure 2-7. Configuration Register MSB... L 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 0 Lock Bit 0 = Unlocked 1 = Locked SOF TagID Length 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 Uplink Data Bit Rate Preamble Operating Mode x 0 1 0 = ITF 1 = PM 1 = EAS 0 0 . . 1 Length ( bit periods ) 0 0 . . 1 0 =1 1 =2 . . . . 1 =8 RF/2(n+1) = 16 bit = 32 bit = 48 bit = 64 bit = 80 bit = 96 bit = 40 bit = 56 bit ITF =Interrogator Talks First Mode PM = Public Mode EAS = Electrical Article Surveillance NRZ = Non Return to Zero 1 = Downlink CRC check mandatory 0 = Reserved Uplink Encoding 0 0 1 1 0 = Manchester 1 = NRZ (Direct Coding) 0 = FDX-B (Biphase) 1 = Reserved Max. Block 1 1 0RR p2 p1 p0 n4 n3 n2 n1 n0 0 R 87 6 0 5 4 3 2 ...LSB 1 0 0 a4 a3 a2 a1 a0 Master Key(1) Downlink Data Rate (DDR)(2) Notes: (1) If master key = 6hex then all test modes are ignored and password protection enabled (2) If DDR = 1 and master key = 6hex or 9hex then data rate = fast, otherwise slow R = reserved for future use, should be set to 0 x = don't care state 3. Transmission Protocol The transmission protocol defines the mechanism to exchange commands and data between the interrogator and the tags. In all but the Public and EAS Mode, the interrogator has complete control over the communication flow – all data transmission being synchronized to interrogator commands and the interrogator field clock – “Interrogator Talks First” (ITF) principle. This means that a tag does not transmit data, unless it has received and properly decoded an interrogator command. The protocol is based on an exchange of • commands from the interrogator to the tag (Downlink mode) • and response from the tag to the interrogator (Uplink mode) 9 4681C–RFID–09/05 3.1 Tag to Interrogator Communication All transmissions from the tag to the interrogator utilize amplitude modulation (ASK) of the RF carrier. This takes place by controlled switching of a resistive load between the coil pads which in turn modulates the RF field generated by the interrogator. The tag is capable of communicating with the interrogator via inductive coupling. Typical examples of the incorporated amplitude modulation is shown in Figure 3-1: • Manchester encoded data signal • Bi-phase encoded data signal • NRZ direct data encoding • Dual pattern data coding is used during the anticollision loop and for an error code response Figure 3-1. NRZ Data Tag to Interrogator - Load Modulation Coding Normal Manchester data coding Td load on Normal Biphase data coding Anticollision dual pattern data coding Td or Td Data "1" load off load on Td load off load on Td load off load on Td Td load off load off load on or Data "0" Td load off load on load off load on 3.1.1 Start of Frame (SOF) Encoding After the reception of a valid interrogator command the tag will reply immediately with a Start of Frame (SOF) pattern. The SOF pattern is made up of a variable length preamble and a fixed 2-bit (Manchester) code violation followed by a half bit duration of unmodulated carrier. The preamble length as set in the configuration block defines the number of (Manchester coded) zero initialization data bits. If the preamble length in the configuration register is set to zero, a single start bit will precede on the code violation. 10 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] Figure 3-2. SOF Pattern SOF Example with p = 4 bit periods Preamble length = 3 2 bit period code violation 3.1.2 Public Mode 1. In Public Mode the cyclic data stream will be preceded by a single SOF pattern after the completion of the POR delay. 2. The variable number of preamble data bits is aimed at easing the interrogator design and optimizing system performance. 3. Within any closed identification system the preamble length for all tags must be identical. 3.2 Interrogator to Tag Communication All commands and data bit streams from the interrogator to the tag are 100% (OOK – On-Off-Key) modulated using a modified 1 out of 4 pulse position coding. Depending on the data, the continuous RF field is interspersed with short field gaps of constant duration and variable separation. The time from one gap to the next may take on one of four discrete values. Each of these represent one of four possible dual bit downlink data codes (00 .. 11) in the data stream (see Figure 3-3). The downlink data transfer speed is dependent on the downlink data rate (DDR) bit set in the tag configuration block, so that selected tags can always understand the interrogator. The minimum write data coding (maximum data rate) is 9 field clocks. This corresponds with the d00 (dref) parameter in Figure 3-3 and Table 3-1 on page 12. Figure 3-3. Interrogator to Tag - Modified 1 out of 4 Pulse Position Coding Uplink mode Sgap d01 Downlink mode d11 d10 dref Wgap d00 11 4681C–RFID–09/05 3.2.1 Start Gap The first command gap is usually slighty longer (~20 field clocks) than the following data gaps. This is referred to as the start gap. All interrogator to tag commands are initiated by such a start gap. As soon as the clock extractor detects a start gap, the tag’s receive damping is switched on. This serves to improve the gap detection of all following data gaps. A start gap can be detected at any time after the completion of the tag’s power on reset delay sequence (RF field-on plus ~3 ms). If a gap is received during this delay sequence, irrespective of whether it is part of a command or a start gap, the delay will restarted. Commands or partial command sequences occurring during the power on reset sequence will not executed. 3.2.2 4PPM Command Encoding The timing between data gaps depends on the Downlink Data Rate (DDR) in the configuration register and is nominally 9 or 13 field clocks for a 00, 17 or 29 field clocks for a 01, 25 or 46 field clocks for a 10 and 33 or 61 field clocks for a 11. The duration of the field gaps themselves lie between 8 and 20 field clocks. Should no gap be detected for more than the maximum 11 gap separation (see Table 3-1), the tag(s) will terminate the present command decoding mode and, if enabled release the receive damping. If an error is detected within the command sequence (e.g. incorrect number of bits received, CRC check failed etc.) the tag will return a dual pattern coded error to the interrogator and ignore the command. The first two bits of every command constitute the Start of Command (SOC) and is always 00. This SOC is used as a timing reference for all following data (see Table 3-1), thus providing an auto-adjustment to allow for varying environmental conditions. Table 3-1. Modified Pulse Position Modulation - Timing Parameters DDR = 1 and Master Key = 6 or 9 DDR = 0 or Master key ≠ 6 or 9 Min. 8 8 13 dref – 7 dref + 9 dref + 25 dref + 41 Parameter Start gap Write gap Remark Symbol Sgap Wgap Min. 8 8 9 dref – 3 dref + 5 dref + 13 Typ. 10 10 – dref dref + 8 dref + 16 Max. 50 20 68 dref + 4 dref + 12 dref + 20 dref + 28 Typ. 10 10 – dref dref + 16 dref + 32 dref + 48 Max. 50 20 72 dref + 8 dref + 24 dref + 40 dref + 56 Unit Tc Tc Tc Tc Tc Tc Tc Reference data 00 Write data coding (gap separation) dref d00 d01 d10 00 data 01 data 10 data Notes: 11 data d11 dref + 21 dref + 24 1. All absolute times assume TC = 1/fC = 8 µs (fC = 125 kHz) 2. All the above timing data is that which should appear on the device terminals so that the device can operate correctly. Depending on the coil used (e.g. Q factor etc.) and the transmission medium, the values implemented in the interrogator could after slightly. 12 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] Figure 3-4. Command “Read Block #23” cmd block addr 00 01 01 01 11 Interrogator command "Read single block 23" S Gap SOF 32 bit data CRC - 16 Tag reply No Modulation Figure 3-5. Command “Write Block #12” cmd block addr lock bit bit31 bit30 00 01 00 11 00 01 11 32 bits data bit1 bit0 10 SGap Interrogator command "Write single block 12" Program delay (≈ 5 ms) 11 00 00 No Modulation CRC - 16 Tag reply 13 4681C–RFID–09/05 4. CRC Error Checking The CRC error checking circuitry generates a 16-bit CRC to ensure the integrity of transmitted and received data packets. The ATA5558 uses the CRC-CCITT (Consultative Committee for International Telegraph and Telephone) for error detection. The 16 bit cyclic redundancy code is calculated using the following polynomial with an initial value of 0x0000: P(X) = x 16 +x 12 +x +x 5 0 The implemented version of the CRC check has the following characteristics: • Reverse CRC-CCITT 16 as described in ISO/IEC 11785 • The CRC 16-bit shift register is initialized to all zeros at the beginning of a command • The incoming data bits are XOR-ed with the MSB of the CRC register and is shifted into the register’s LSB • After all data bits have been processed, the CRC register contains the CRC-16 code. • Reversibility - The original data together with associated CRC, when fed back into the same CRC generator will regenerate the initial value (all zero’s). Should a CRC be required, both the tag and interrogator must use the above CRC polynomial. During read/write operations, a CRC can be attached to information by either the interrogator and/or the tag In the case of downlink communication, a CRC (CRC_d) can be attached to information transmitted from the interrogator to the tag(s) (see Figure 4-2 on page 15). This is evaluated by the tag(s) to ensure correct transmission. During the uplink phase of the read commands the tag replies with the requested data block(s) followed by an uplink CRC (CRC_u). This CRC_u is generated in the tag’s CRC generator, from the downlink address, CRC_d (if used) and the returned data (see Figure 4-3 on page 16 a, b, c). So by initializing the interrogator’s CRC generator with the same address and CRC_d (if used), then subsequently updating it with the returned data and uplink CRC_u, the integrity of both the address understood by the tag and data itself can be verified. On receiving a response from the tag which includes a CRC_u, it is recommended that the interrogator verifies this. If it is found to be incorrect, the interrogator should take the appropriate actions. These actions are left to the discretion of the system designer. During the anticollision detection, the CRC can also be used as a means of tag identification. A tag which is successfully selected by one of the select commands or as the result of an anticollision elimination cycle, will always reply with a CRC. This is generated from it’s own Tag ID (see Figure 4-3 on page 16 d) and is always preceded by an SOF pattern. This also provides an additional means of double checking whether the intended tag has been selected. For any write command, if the bit 10 of the configuration register = 1, the usage of the CRC for this communication is mandatory. Failure to include or verify a CRC results in the tag aborting the command execution and returning an error code. If the configuration register bit 10 = 0, the Write CRC usage is optional. In this case, the CRC is handled in the same manner as a read command i.e. the CRC is only evaluated if attached. Should no CRC be transmitted and the configuration register bit 10 = 0, then the command will always be executed. 14 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] Figure 4-1. Schematic Diagram of CRC Generation Data in P (X) = X0 X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 lsb msb Figure 4-2. Examples of Downlink CRC Generation (a) Read Multiple Blocks lsb .......... msb 11 11 01 lsb ........... msb 0110 00 lsb .............................................. msb 0110 1110 1000 0010 end address (1F hex) start address (06 hex) Interrogator CRC Generator after 12 shift operations CRC_d = 4167hex (b) Read Single Block lsb .............. msb 0110 00 lsb .................................................. msb 0110 0011 0000 0110 address (06 hex) Interrogator CRC generator after 6 shift operations CRC_d = 60C6hex (c) Write lsb .................................................. msb 0110 000 0 0000 1010 10 lsb .............. msb 1100 10 lsb .................................................. msb 1111 0111 1010 0100 data (32 bits) (5000 0006 hex) lock bit (locked) address (13 hex) Interrogator CRC generator after 40 shift operations CRC_d = 25EF hex Data from interrogator CRC Generator tag or interrogator 15 4681C–RFID–09/05 Figure 4-3. Examples of Uplink CRC Generation (a) Read Multiple Blocks using downlink CRC lsb .................................................................... msb 1110 0110 1010 0010 1100 0100 1000 0000 lsb ................................................................... msb 1111 0111 1011 0011 1101 0101 1001 0001 Data from address 06h (0123 4567 hex) Data from address 07h (89ABCDEF hex) lsb .......................................... msb 0111 1010 0100 1011 lsb .......... msb 11 10 00 lsb ........... msb 0110 00 lsb ................................................ msb 1010 1010 1001 0101 CRC_d from interrogator (D25E hex) end address (07hex) start address (06hex) Tag CRC Generator after 92 shift operations CRC_u = A955hex (b) Read Single Block without downlink CRC lsb ............................................................... msb 0000 0000 0000 0000 0011 0011 0011 0011 lsb ............ msb 0110 00 lsb .................................................. msb 1010 0001 0100 0110 Data from address 06h (CCCC 0000hex) address (06hex) Tag CRC Generator after 38 shift operations CRC_u = 6285hex (c) Read Single Block with downlink CRC lsb .............................................................. msb 1010 1010 1010 1010 0101 0101 0101 0101 Data from address 07h (AAAA 5555 hex) lsb .......................................... msb 0010 1001 0100 0010 lsb ........... msb 1010 10 lsb .................................................. msb 0101 1001 1100 0000 CRC_d from interrogator (4294 hex) start address (15hex) Tag CRC generator after 54 shift operations CRC_u = 039Ahex (d) Select Tag (16 bit TagID) lsb ........................msb 1100 0100 1000 0000 lsb ................................................. msb 0000 1100 1110 0100 TagID ( 0123hex) Data from tag Data from interrogator Tag CRC Generator after 16 shift operations CRC_u = 2730hex CRC Generator tag or interrogator 16 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] 5. Operating Modes After initialization, the Operating Mode (Configuration block bits 23 and 24) is interrogated and depending on it’s state, the device will go into either the READY state of the “Interrogator Talks First” (ITF) mode or the Public Mode’s PM READY state if the PM bit is set or the “Electronic Article Surveillance” (EAS) mode is selected. 5.1 Interrogator Talks First Mode (ITF) For multi-tag applications, the ATA5558 is used in the “Interrogator Talks First” (ITF) mode with anticollision handling capability. In this mode, the tag starts up in the READY state, where it remains silent and waits for further interrogator commands before communication can take place. 5.2 Tag State Machine Any tag can find itself in one of the following states: • POWER DOWN • PM READY (for PM or EAS modes only) • READY (ITF mode) • SELECTED • QUIET In the state diagram shown in Figure 5-1 on page 18, a state transition takes place by applying or removing the field (power on/off) or via one of the commands Select, SelectAll, SelectGroup, ResetSelected or ResetToReady. When a tag is unable to decode or process an interrogator command (e.g. CRC or bit frame error), it will remain in the current state. Depending on the state, tag(s) will only accept certain commands. 5.3 Power Down State The tag is in the Power Down state when there is not enough energy in the interrogator field to activate the tag. The ATA5558 commences a power-on initialization delay with an activated weak damping level to achieve a field strength threshold for stable operation. 5.4 READY State (ITF) The ATA5558 tag enters the READY state after it has been activated by the interrogator (RF-field on) or after receiving either a ResetToReady or ResetSelected command (the EAS and PM deactivated). The READY state is the initial anticollision state, and in general all tags on this state are unidentified. 5.5 Selected State Before a tag can in any way be accessed, it must first be selected. Tag selection can take place individually in which case they find themselves within the Selected state. They can enter the Selected state as a result of receiving an explicit Select command with the matching Tag ID. In this way, only one tag can theoretically be in the Selected state at any one time. If a tag should find itself in the Selected state and a second tag is selected by a subsequent Select command, the first tag will automatically proceed into the Quiet state. 17 4681C–RFID–09/05 It is possible to carry out commands simultaneously on more than one tag. To do this they must all first be selected by specifying a group of tags within the READY state and putting the group into the Selected state. This is performed by using a SelectGroup command with a matching partial Tag ID pattern. A group of tags in the Selected state may be written simultaneously with identical blocks of data. Data verification and checksum errors are reported by the tags using a special dual pattern code. Tags within the Selected state will automatically drop into the Quiet state and be excluded from subsequent anticollision detection, if a subsequent Select or GetID command is received. Selection can also take place on tag groups with non-matching Tag ID patterns using the SelectNGroup command. This could be useful for example, to check a storage crate for items which do not match a certain selection criteria (e.g. color or dispatch destination), so a SelectNGroup command with the Tag ID mask set to the color black will GroupSelect all non-black items. If no tag responds with a SOF pattern, then there are no black items present. Figure 5-1. Tag State Diagram Power On (PM or EAS only) PM READY (continuous data transmission) ResetToReady or invalid command (PM or EAS only) Start Gap POWER DOWN READY (ITF mode ) Power On (ITFMode ) Arbitration lost/ TagID eliminated GetID All sucessfull select commands ResetToReady ResetToReady, Reset Selected Anticollision detection loop Select or GroupSelect with matching TagID or SelectAll TagID Identified QUIET Select, GroupSelect or GetID opcode SELECTED Implicit state change Command initated state transition Read/Write/Login 18 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] 5.6 Quiet State The tag goes into the Quiet state from the Selected state when a new selection takes place i.e. a Select or a GetID command is received. Unlike the READY state, the tag’s Tag ID in this state is known. Tags in the Quiet state are excluded from subsequent anticollision detection. 5.7 Public Mode (PM) and PM READY State In the Public Mode, communication commences with a single “Start of Frame” pattern (SOF), followed by a continuous stream of serialized user data which is read cyclically from the user memory. This starts with block 0, bit 31 and continues sequentially through to bit 0 of the final block address defined by the configuration parameter MAXBLOCK. After reaching the MAXBLOCK address, data transmission repeats with block 0, bit 31. If, for example MAXBLOCK were set to 1, block 0 and 1 would be continuously transmitted. This transmission process continues indefinitely until terminated by either switching the field off or on the receipt of a valid interrogator command. On the start of a new command the tag will proceed temporarily from the PM READY state into the (ITF) READY state. If the command is valid, it will be executed and the tag state changes as if in the ITF mode (see Figure 5-1 on page 18). If the command is invalid, then it will drop back into the PM READY state and continue to transmit data. To restart the public mode transmission, the tag must be re-initialized by reapplying the field (POR) or by using a ResetToReady command. Figure 5-2. Public Mode Start Up POR initialisation delay Start of Frame (SOF) Data Block (Maxblock ) Bit position 31 30 29 28 27 26 25 4 3 2 1 0 31 30 29 28 27 26 Data Block 0 Continue from Data Block 0 1 0 0 1 1 0 0 1 0 0 1 1 1 0 0 1 1 0 POR Check Operating Mode (= PM) Example data values 5.8 Electronic Article Surveillance (EAS) The EAS Mode is intended for retail article surveillance whereby the device will be physically attached to retail articles in a store or supermarket. The device will be preprogrammed into an ”unpaid state” before entering the sales area by programming the block 0 to MAXBLOCK of the user memory to all 0s. For convenience reasons MAXBLOCK should be set to 0 in the configuration word. To increase security, the memory pages containing block 0 to MAXBLOCK should be assigned a write password security level (see password protection). Once the article has been purchased at the cash desk, the device is programmed into a “paid state” by writing the block 0 with all 1 s, using the appropriate password (if necessary). As soon as an “unpaid” device enters an interrogator field, it will modulate the interrogator field with an RF/2 signal. This can be detected by the surveillance interrogator and used to trigger an appropriate audio or visual warning. A “paid” device will remain silent. As in the Public Mode, the device will revert to ITF mode READY state as soon as it receives a valid interrogator command. By reapplying the field (POR) or using a ResetToReady command, the device returns to EAS mode. 19 4681C–RFID–09/05 Figure 5-3. EAS Startup POR initialisation delay POR initialisation delay "Unpaid" Device (Block 0 = all '0's) "Paid" Device (Block 0 = all '1's) POR Check Operating Mode (= EAS) POR Check Operating Mode (= EAS) 6. Anticollision Protocol The aim of the anticollision protocol and associated arbitration process is to detect and identify the Tag ID’s of all tags within the READY state which are present within range of the interrogator field. The interrogator masters all communication with single or multiple tags. Tag arbitration communication is initiated by issuing the GetID command. All tags in the READY state will then enter the anticollision detection loop and synchronously start to transmit an identification response that represents the tag’s individual unique Tag ID code. Using an iterative bit-wise sorting algorithm on these Tag ID’s, the interrogator is capable of eliminating all but one tag. This remaining tag is thus selected and can be accessed directly by following commands. Tags eliminated during the detection loop are muted, drop back into the READY state to participate in the next detection cycle. A typical anticollision procedure is illustrated in the following scheme: a) The interrogator starts the anticollision detection by sending a GetID command. Any previously eliminated and muted tag will be put into the READY state. All tags in the READY state participate initially in the anticollision detection loop. If nothing is known of the Tag ID’s within range, then the GetID command includes no further parameters and the detection group encompasses all tags. After a predefined number of field clock cycles, all tags within range reply by synchronously transmitting a SOF pattern followed by their own respective Tag ID(MSB). Anticollision detection can be reduced to a subgroup of tags by passing a partial Tag ID pattern as Tag ID command parameter. These bits represent the most significant bits of the Tag ID subgroup. Anticollision detection will then be carried out on this subgroup, continuing as above with the synchronous reply from all constituent tags, followed by their most significant unknown Tag ID bit(s). 20 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] b) The interrogator can detect whether any tag is present. If no SOF pattern is returned then there is no tag present within the detection group so the process continues with (a). c) The interrogator checks the tag responses bit-wise within the anticollision loop. If one or more active tags are within range, the interrogator will sequentially scan the Tag ID bits from the most significant through to the least significant bits. Each time slot corresponds to a particular Tag ID bit position. All tags reply simultaneously with dual pattern modulated data, the response signals being superimposed on one another. A damped signal will thus overwrite a non-damped signal so that a logical 1 Tag ID bit will prevail over a logical 0 bit. d) The interrogator checks and eliminates tags. If the interrogator detects a Tag ID logical 1 bit, it acknowledges reception by broadcasting a gap in the field signal. This can be monitored and evaluated by all tags within the detection group. Otherwise a Tag ID logical 0 bit induces no reaction from the interrogator. On observing an acknowledge gap, any individual tag can, by checking the state of it’s own current Tag ID bit, deduce whether it should remain in the current anticollision detection loop (Tag ID bit = 1) or whether it should eliminate itself from the detection group (Tag ID bit = 0). Eliminated tags will be muted and fall back into the READY state where they take no further part in the current detection loop. They remain in this state until the next anticollision loop is started by a new GetID command. Continue to (a) Non eliminated tags remain in the detection loop and if the final Tag ID bit has not been reached then the next Tag ID bit is interrogated in (c) otherwise (e). e) End of a single anticollision loop By the time the final Tag ID bit has been interrogated, there will be only one remaining active tag within range – all others having been eliminated during the previous interactions. Assuming no new tags have entered the interrogation since the start of the anticollision loop and that all the signals have been correctly interpreted, the interrogator should at this stage be able to identify the associated Tag ID. This active tag is set automatically into the Selected state and replies with the anticollision response which consists of an SOF followed a 16 bit CRC generated from it’s own Tag ID. If the received CRC matches the Tag ID the interrogator may continue with (a) or (f). If the received CRC is corrupted or does not match the calculated 16 bit value the interrogator will issue a ResetSelected command to transfer this improperly selected tag back into the READY state. Continue to (a). f) The interrogator communicates directly with tag in Selected state. At this stage the single identified and selected tag can undergo direct communication with the interrogator and can be read and written with either Read, Write or Login commands. This tag remains selected until the interrogator starts a new anticollision loop with a new GetID command, or if other tags are addressed directly using a Select or GroupSelect command. The selected tag then drops into the Quiet state where it is excluded from all future anticollision detection loops. Continue to (a). 21 4681C–RFID–09/05 Figure 6-1. Anticollision Loop Tag (one of many slaves) Start Interrogator (single master) Start N Partial TagID Transmit GetID command READY state Y N Transmit GetID command/ parameters GetID command GetID command? No Tag Y Mask bit parameters Parameters received? Y N Select Subgroup x=N N SOF? (Tag present?) SOF Transmit SOF Y N TagID(x)=1? Transmit TagID(x) TagID(x)bit Y Gap Transmit Gap (Acknowledge) Y N Gap? N Selected TagID(x) = 0 Selected TagID(x) = 1 TagID(x) = 1? TagID(x) = 0? N Y x=x+1 (next bit) x=x+1 (next bit) Y N Last TagID bit? N Last TagID bit? Y Y N Transmit SOF + CRC of selected Tag Selected CRC correct? SOF + CRC Y Detection Error Selected TagID found SELECT state 22 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] Figure 6-2. GetID Command with Partially Known Tag ID SOC GetID even 00 00 00 10 A 10 00 2 10 00 3 11 Interrogator command GetID (TagIDpart = "A23") TTag TIR SGap Figure 6-3. Subsequent Tag Responses in Anticollision Loop (Two Alternative Tag IDs) Anticollision response from all tags. SOF Anticollision response from all tags with '1' in current TagID position (TagID = A233 and/or A232) SOF '0' '0' '1' 2 bit period 2 bit period 2 bit period Interrogator acknowledge gap subsequent TagID bits TTag Tag response for TagID's "A232" or "A233" TTag TTag '1' 2 bit period Anticollision response from remaining tag with '1' in last TagID position (TagID = A233) '0' SOF Alternative A (TagID = "A233") '1' '1' '1' '0' '1' '1' '0' '0' Interrogator acknowledge gap TTag final TagID bit T1 16 bit Manchester coded CRC (= "7D2C" ) Final Tag response for TagID "A233" + CRC '0' 2 bit period Anticollision response from remaining tag with '1' in last TagID position (TagID = A232) '0' SOF Alternative B (TagID = "A232") '1' '1' '0' '0' '1' '1' '0' '1' TTag final TagID bit T0 16 bit Manchester coded CRC (= "6D0D" ) Final tag response for TagID "A232" + CRC 23 4681C–RFID–09/05 Table 6-1. Parameter Anti-collision Timing Remark Symbol Formula TBit=fC/32 ≥0 Unit Tag reaction time Tag to Interrogator response time End of anticollision loop to start of SOF (and CRC) response Note: End of start gap to start of tag command processing End of final command gap to start of tag SOF acknowledge Final bit of Tag ID = 0 Final bit of Tag ID = 1 TIR TC 84 116 50 TC TC TC TC TTag T0 T1 d11max + 1½ × TBit (see Figure 4-1 on page 15) 2 × TC + 1½ × TBit = TTag DDR = 1 DDR = 0 DDR = 1 84 DDR = 0 116 TC In the above example the following is assumed: fC = 125 kHz; TC = 1/fC = 8 µs and a data rate of fC/32; so a bit period TBit = 32 × TC 7. Command Set The first two bits of any interrogator command are called Start Of Command (SOC) and are always 00. This pulse interval is used for auto calibration purposes. The following series of dual bit packets define the interrogator command opcodes and the command dependant parameter information. A command overview is given in Table 7-1 below Table 7-1. Command List of ATA5558 Supported Commands SOC 00 00 00 00 00 00 00 00 00 00 00 00 00 Opcode 01 01 01 01 11 01 11 10 01 11 01 10 10 00 00 00 00 00 1 00 00 10 00 10 0[0]n 1 10 1[0]n 1 11 10 00 00 Number of Parameter bits Description Read Single Block Read Multiple Blocks Write Single Block Login Write Login Read GetID GetID (Tag ID-part, even) GetID (Tag ID-part, odd) Select (Tag ID) SelectAll SelectGroup SelectNGroup ResetSelected 6 (+ 16 CRC_d) 12 (+ 16 CRC_d) 40 (+ 16 CRC_d) 32 32 None Length of partial Tag ID Length of partial Tag ID Length of Tag ID None Length of Tag ID mask Length of Tag ID mask None Read single 32 bit data block and CRC_u (+ optional downlink CRC_d) Read multiple data blocks and CRC_u (+ optional downlink CRC_d) Write a single block (+ optional downlink CRC_d) Login for write PWD protected access Login for read PWD protected access Starts a complete new anticollision loop Anticollision loop with partial Tag ID, with even number of matching Tag ID bits. Anticollision loop with partial Tag ID, with odd number of matching Tag ID bits. Puts specified tag into Selected state Selects all tags in the RF field Select a specific group of tags Select all tags which are NOT members of the specified group Reset selected tag to READY state without reloading configuration register Reset all tags in the RF field to READY state and reload configuration register from system memory (block #63) Arms tag for ClearAll command Clears memory except traceability data (with optional constant CRC_d = 96ADh) ResetToReady ArmClear ClearAll 00 00 00 11 00 00 00 11 00 10 00 01 01 11 11 None 6× 0 34 × 0 (+ 16 CRC_d) 24 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] Figure 7-1. Command Format Command cmd Read multiple blocks 0 0 0 1 OK Response end addr CRC_d Error Response start addr XXXXXXXXXXXX fn (start addr,end addr) SOF Data CRC_u SOF fn(start addr,end addr,(CRC_d),data Error code dual pattern cmd Read single block 0 0 0 1 addr XXXXXX fn (addr) CRC_d SOF Data CRC_u SOF fn(addr,data,(CRC_d)) Error code dual pattern cmd Write single block 0 0 0 1 addr lock data bits CRC_d XXXXXX0 L 31............0 fn (addr,lock,data) SOF SOF Error code dual pattern cmd Select 0 0 0 00 0 TagID SOF CRC_u None cmd SelectCRC fn (TagID) 0 0 0 0 0 1 CRC(TagID) SOF None cmd 0 0 0 0 0 0 Anticollision Response even GetID cmd None partial_TagID Anticollision Response None 0 0 0 0 0 0 TagID[msb],TagID[msb-1]..TagID[msb-(n-1)] GetID (Even partial TagID) cmd odd 0 ≤ n ≤ Length(TagID) where n : even partial_TagID TagID[msb],TagID[msb-1]...TagID[msb-(n-1)] 00001 GetID (Odd partial TagID) 0 ≤ n ≤ Length(TagID)-1 where n : odd Anticollision Response None Select All 0 01 0 0 0 SOF SOF Error code dual pattern Error code dual pattern SelectGroup m+n: even 0 ≤ m+n ≤ Length(TagID) 0 0 1 0 0 [(0)m 1] TagID(msb-m) ... TagID(msb-m-n) SOF SOF variable length mask positioning pattern(1) variable length (n) TagID Select pattern(2) SelectNGroup m+n: even 0 ≤ m+n ≤ Length(TagID) 0 0 1 0 1 [(0)m 1] TagID(msb-m) ... TagID(msb-m-n) SOF SOF Error code dual pattern variable length mask positioning pattern(1) variable length (n) TagID Select pattern(2) Note: Note: 1. The leftmost position of the TagID select mask is determined by m '0' bits followed by a single '1' bit. These bit positions can be regarded as don't care bit positions. 2. The TagID select mask is a variable (n) bits long. It starts immediately after the positioning pattern and can be terminated as required with the end of the command. All TagID lsb bits not defined are don't care. 25 4681C–RFID–09/05 Figure 7-2. Command Format (Continued) Command OK Response Error Response cmd Read PWD addr Login Read Read PWD SOF SOF Error code dual pattern 0 0 0 1 1 1 0 1 1 0 1 0 PWD(31)...PWD(0) cmd Write PWD addr Login Write Write PWD SOF SOF Error code dual pattern 0 0 0 1 1 1 0 1 1 1 1 0 PWD(31)...PWD(0) cmd ResetToReady 0011000000 cmd SOF SOF Error code dual pattern Reset Selected 0011100000 cmd SOF SOF Error code dual pattern ArmClear 0011101000000000 32 '0' cmd data bits 0 0 0 1 0 1 1 1 1 1 0 0 0 0......0 0 CRC_d constant CRC (96ADh) SOF SOF Error code dual pattern ClearAll SOF SOF Error code dual pattern 7.1 Error Response If a command sequence is in any case invalid, the tag answers immediately with one of the error codes (see Table 7-2). This is made up of an SOF pattern followed by a 4-bit dual pattern coded data word. Table 7-2. Error Code 0111 1110 0010 0100 1000 1101 1011 1010 0110 others Error Codes Description Command format error – incorrect number of bits Corrupt command (1 out of 4) encoding Attempt to write a locked block – write command aborted Attempt to write a protected block without a login – write command aborted Login/Write command format error Incorrect Login password CRC error in command stream – command aborted Program 0 verification error – unreliable zero level (degraded data retention) Program 1 verification error – unreliable one level (degraded data retention) Reserved for future use 26 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] 7.2 Read Single Block A Read Single Block command is executed on a tag in the Selected state. It serially reads a complete 32-bit tag data block. A downlink CRC (CRC_d) can be optionally included. This acts as a check for the block address. If included, the tag will always check the CRC_d and abort the command if it not compatible with the received address. If omitted, the tag will perform no downlink CRC check. The tag responds to a single block read command with the requested 32-bit data block which is always followed by a 16-bit uplink CRC (CRC_u) to ensure data and address integrity. A read protected or non-existent memory block will return a block of 1 data bits (FFFF FFFF). A successful execution of a LoginRead command is necessary before reading a protected memory block. It should be noted that the 16-bit CRC_u is generated from both the block address parameter and retrieved data. So that it acts as a check for the complete command transaction. From the received CRC_u, the interrogator can ensure that the data is correct and that it was read from the correct requested block address. Table 7-3. Command Interrogator Command Parameters Parameter 1 CRC (optional) Read Single Block = 00 01 4 bits Block Address 6 bits (MSB first) CRC_d (Block Addr) 16 bits (MSB first) Table 7-4. SOF Tag Response Data CRC Start of Frame 3 .. 10-bit periods Note: 1. optional Data Block 32 bits (MSB first) CRC_u (Block Addr + [CRC_d(1)] +Data) 16 bits (MSB first) 7.3 Read Multiple Blocks A Read Multiple Blocks command is executed on a tag in the Selected state. It serially reads an array of consecutive 32-bit tag data blocks from a start address through to and including an end address. A downlink CRC (CRC_d) can be optionally included. This acts as a check for both block address parameters. If included the tag will always check the CRC_d and abort the command if it is not compatible with the received addresses. If omitted, the tag will perform no downlink CRC check. The tag responds to a read command with the requested 32-bit data blocks which are always followed by a single 16-bit uplink CRC (CRC_u) to ensure data and address integrity. A read protected or non-existent memory block will return a block of 1 data bits (FFFF FFFF). A successful execution of a LoginRead command is necessary before reading a memory array including protected memory blocks. It should be noted that the 16 bit CRC_u is generated from both the address parameters and retrieved data so that it acts as a check for the complete command transaction. From the received CRC_u, the interrogator can ensure that the data is correct and that it was read from the correct requested block address range. 27 4681C–RFID–09/05 Table 7-5. Command Interrogator Command Parameters Parameter 1 Parameter 2 CRC (optional) Read = 00 01 4 bit Start Block Address 6 bits (MSB first) End Block Address 6 bits (MSB first) CRC_d (Start Block Addr + End Block Addr) 16 bits (MSB first) Table 7-6. SOF Tag Response Data CRC Start of Frame 3 .. 10-bit period Multiple Data Blocks ((EndAddr – StartAddr + 1) × 32) bits (MSB first) CRC_u (Start Block Addr + End Block Addr + [CRC_d*] + Data) 16 bits (MSB first) 7.4 Write Single Block The Write Single Block command only effects tag(s) which have been previously been put in the Selected state. It performs the programming of a specific block address with a 32-bit block of data and associated lock bit. For password protected memory blocks the LoginWrite command has to be executed first, otherwise the programming will fail and an error code will be returned. Memory blocks which have a 1 in the lock bit are locked and cannot be written. The command protocol includes downlink CRC (CRC_d) which is used to check the downlink address and data. This CRC_d can be mandatory or optional depending on the state of bit 10 of the configuration register. If set to 1 , the CRC_d must always be included and correct for the data programming to take place. If set to 0, the CRC_d is optional i.e. it is only checked if the CRC data is present. On receiving the Write command, and if necessary checking the CRC_d, the tag will start the EEPROM programming sequence. The maximum EEPROM program time per block (including the lock bit) is 6 ms. This programming cycle includes an automatic read verification phase which makes sure that the data has been programmed securely thus ensuring satisfactory long term data retention. To signal the completion of a successful programming cycle, the tag returns a single SOF pattern. If for any reason the programming of the data block fails, the tag will generate the corresponding error code. The error code bits are dual pattern coded (see Figure 3-1 on page 10) and preceded by a SOF pattern. An attempt to write to a locked block address or a downlink CRC error causes an immediate abort of the programming cycle followed by the transmission of the corresponding error response. In the case of an EEPROM data verification failure, the error response is returned after the completion of the programming cycle. Table 7-7. Command Interrogator Command Parameters Parameter 1 Parameter 2 0 + Lock bit Parameter 3 CRC(1) Write Single Block = 00 01 4 bits Note: Block Address 6 bits (MSB first) Write Data 32 bits (MSB first) CRC_d (Block Addr + Lock + Data) 16 bits (MSB first) 2 bits 1. The downlink CRC (CRC_d) must be appended if bit 10 of the configuration register = 1, otherwise it is optional. 28 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] Table 7-8. SOF Tag Response Error Flags Start of Frame 3 .. 10-bit period Present on error only 4-bit – dual pattern code 7.5 LoginRead The purpose of the LoginRead command is to release the read protection on all read protected data blocks within the user memory. A tag in the Selected state will respond with a SOF pattern if the transmitted read password matches the data stored in the tag’s system memory block 36hex (Read PWD). In the case of a non-matching read password the tag will reply with a SOF pattern followed by an error code. After a successful LoginRead command, all read protected memory blocks may be read normally. This positive login status remains valid until a new tag is selected or the tag is reset. Table 7-9. Command Interrogator Command Parameters Parameter 1 11 01 10 (36hex) Parameter 2 10 Parameter 3 LoginRead = 00 01 4 bits Read Password 32 bit (MSB first) 6 bits (MSB first) 2 bits Table 7-10. SOF Tag Response Error Flags Start of Frame 3 .. 10-bit period Present on error only 4-bit – dual pattern code 7.6 LoginWrite The purpose of the LoginWrite command is to release the write protection on all write protected data blocks within the user memory. A tag in the Selected state responds with a SOF pattern if the transmitted write password matches the data stored in the tag’s system memory block 37hex (Write PWD). In the case of a non-matching write password the tag will reply with an SOF followed by an error code. After a successful LoginWrite command any write protected memory block may be modified, as long as the addressed memory block is not already locked. The positive login status is valid until a new tag is selected or the tag is reset. Table 7-11. Command Interrogator Command Parameters Parameter 1 11 01 11 (37hex) Parameter 2 10 Parameter 3 LoginWrite = 00 01 4 bits Write Password 32 bits (MSB first) 6 bits (MSB first) 2 bits Table 7-12. SOF Tag Response Error Flags Start of Frame 3 .. 10-bit period Present on error only 4-bit – dual pattern code 29 4681C–RFID–09/05 7.7 ResetSelected A ResetSelected command will set all currently selected tag(s) back into the ITF mode’s READY state. The tag(s) answers with a SOF pattern and will be able to participate in future anticollision sequences. If either PM or EAS is enabled, this command will not return a selected back into public Mode Ready State ,i.e., the device will not start to transmit public mode data. Table 7-13. Command Interrogator Command ResetSelected = 00 11 10 00 00 10 bits Table 7-14. SOF Tag Response Start of Frame 3 .. 10 bit-period 7.8 ResetToReady In ITF mode, a ResetToReady command will set all tags within range of the RF field back into the Ready state. If either PM or EAS is enabled, the ResetToReady will set the tag back into the PM Ready state where it will start to transmit PM data. All tags will answer with the SOF pattern. In READY state they can then participate in future anticollision sequences. The ResetToReady command reloads the configuration register from system memory block #63. Table 7-15. Command Interrogator Command ResetToReady = 00 11 00 00 00 10 bits Table 7-16. SOF Tag response Start of Frame 3 .. 10-bit period 7.9 Select When receiving a Select command, the addressed tag responds with the 16 bit CRC of the Tag ID and immediately enters the Selected state. After selection, the interrogator may communicate with the selected tag using any valid Read, Write or Login commands. If the interrogator sends a new GetID or Select (another tag) command, the currently selected tag enters the Quiet state automatically. 30 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] Table 7-17. Command Interrogator Command Parameters Parameter Select = 00 00 00 6 bits Tag ID bits (MSB first) Table 7-18. SOF Tag Response CRC Start of Frame 3 .. 10-bit period CRC_u (Tag ID) 16 bits (MSB first) 7.10 GetID When receiving a general GetID command, all tags in the READY state will enter the anticollision loop and take part in the deterministic arbitration sequence All activated tags will reply synchronously with the same anticollision response. This specific anticollision signature consists of a SOF pattern followed by subsequent dual pattern coded Tag ID bit(s) as illustrated in Figure 3-1 on page 10 and Figure 6-3 on page 23. Table 7-19. Command Interrogator Command GetID = 00 00 00 6 bits Table 7-20. SOF Tag Response Subsequent Tag ID Bit(s) Start of Frame 3 .. 10-bit period Dual pattern code × 2 bits periods (MSB first) 7.11 Get_ID (Partial Tag ID) Any anticollision loop starts with the interrogator’s GetID command. All tags in the READY state with a matching partial Tag ID will reply synchronously with their own personal anticollision response. This consists of an initial SOF pattern followed by the Tag ID bit(s) in dual pattern coding which continue until the complete Tag ID has been sent or until the tag is eliminated from the search. Table 7-21. Command Interrogator Command Parameters (Even Number of (n) Known Tag ID Bits) Parameter GetID (Tag ID) = 00 00 00 6 bits Tag ID [MSB], Tag ID [MSB-1],.......Tag ID[MSB-(n-1)] bits (MSB first); where n = 2, 4, 6, 8.... 31 4681C–RFID–09/05 Table 7-22. Command Interrogator Command Parameters (Odd Number of (n) Known Tag ID Bits) Parameter GetID (Tag ID) = 00 00 1 5 bits Tag ID[msb], Tag ID[msb-1],.........Tag ID[MSB-(n-1)] bits (MSB first); where n = 1, 3, 5, 7, .. Table 7-23. SOF Tag Response Subsequent Tag ID bit(s) Start of Frame 3 .. 10-bit period Dual pattern code × 2 bits periods 7.12 SelectAll When receiving the SelectAll command, all tags in the READY state will enter the Selected state and answer with the SOF pattern. This allows the rapid global configuration and personalization of a collection of tags without having to select and program each tag sequentially. Table 7-24. Command Interrogator Command SelectAll = 00 10 00 6 bits Table 7-25. SOF Tag Response Start of Frame 3 .. 10-bit period 32 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] 7.13 SelectGroup When receiving the SelectGroup command, all tags in the READY state with the matching partial Tag ID will enter the Selected state and answer with the SOF pattern. The partial Tag ID can vary in length. It’s pattern position relative to the Tag ID is set by the first (leftmost) 1 in the command parameter. The preceeding 0 b its act solely as “don’t care” spacer bits. This “mask header” is not part of the actual partial Tag ID. The mask pattern follows the mask header and is terminated by the end of command. Example of SelectGroup Parameters: Sample Tag ID 6CB9 : 1) Command Parameter: Partial Tag ID: 2) Command Parameter: Partial Tag ID: 3) Command Parameter: Partial Tag ID: 4) Command Parameter: Partial Tag ID: 01 10 11 00 10 11 10 01 The above Tag ID would be selected by all the following GroupSelect command parameters: 0 00 00 00 10 10 11 XX XX XX X0 10 11 XX XX 0 00 00 00 00 01 11 10 XX XX XX XX XX 11 10 XX 0 00 00 00 00 00 00 00 11 XX XX XX XX XX XX XX X1 1 01 10 11 00 01 10 11 00 XX XX XX Leading 0 don’t care mask bits + 1 = mask header (not part of Partial Tag ID) X = don’t care mask bits Table 7-26. Command Interrogator Command Parameters Parameter 1 Parameter 2 SelectGroup = 00 10 0 5 bits Mask header: × 0 + 1 bits, (m = 1 .. Tag ID length) Partial Tag ID bits, (1 .. Tag IDTag ID length) Table 7-27. SOF Tag Response Start of Frame 3 .. 10-bit period 33 4681C–RFID–09/05 7.14 SelectNGroup When receiving the SelectNGroup command, all tags in the READY state which do not match the partial Tag ID will enter the Selected state and answer with the SOF pattern. The partial Tag ID can vary length. It’s pattern position relative to the Tag ID is set by the first (leftmost) 1 in the command parameter. The preceeding 0 bits act solely as ”don’t care” spacer bits. This “mask header” is not part of the actual partial Tag ID. The mask pattern follows the mask header and is terminated by the end of command. Example of SelectNGroup Parameters: Sample Tag ID 6CB9 : 1) Command Parameter: Partial Tag ID: 2) Command Parameter: Partial Tag ID: 3) Command Parameter: Partial Tag ID: 4) Command Parameter: Partial Tag ID: 01 10 11 00 10 11 10 01 The above Tag ID would be selected by all the following GroupNSelect command parameters: 0 00 00 00 10 00 11 XX XX XX X0 00 11 XX XX 0 00 00 00 00 01 11 11 XX XX XX XX XX 11 11 XX 0 00 00 00 00 00 00 00 10 XX XX XX XX XX XX XX X0 1 00 10 11 00 10 11 10 01 00 10 11 00 10 11 10 01 Leading 0 don’t care mask bits + 1 = mask header (not part of Partial Tag ID) X = don’t care mask bits Table 7-28. Command Interrogator Command Parameters Parameter 1 Parameter 2 SelectGroup = 00 10 1 5 bits Mask header: × 0 + 1 bits; m = 1 .. Tag ID length – 2 Matching pattern section of Tag ID bits; n = 2 .. Table 7-29. SOF Tag Response Start of Frame 3 .. 10-bit period 34 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] 7.15 ArmClear A selected tag, when receiving the ArmClear command with the Master Key NOT set to 6 will prepare the device for a subsequent ClearAll command. If this command is followed by any command other than a ClearAll, it will become disarmed. In which case the ArmClear must be repeated before a ClearAll can be successfully executed. Table 7-30. Command Interrogator Command Parameter 00 00 00 ArmClear = 00 11 00 10 00 10 bits 6 bits Table 7-31. SOF Tag Response Start of Frame 3 .. 10-bit period 7.16 ClearAll Tags in the Selected state, if previously armed by the ArmClear command will clear all memory blocks and their lock bits with the exception of the traceability data blocks (see Figure 2-3 on page 4 in “Memory” section). The ClearAll command includes an EEPROM programming sequence. The maximum EEPROM programming time is 6 ms. On completion of a successful clear the tag replies with a single SOF pattern. If for any reason the clear operation fails, the tag will generate the corresponding error code. The error code bits are dual pattern coded (see Figure 3-2 on page 11 and Table 7-2 on page 26) and are preceded by a SOF pattern. If the constant downlink checksum CRC_d (if appended) is incorrect, the clear operation is aborted and an error response is returned immediately. Table 7-32. Command Interrogator Command Parameters Parameter 1 01 11 11 Parameter 2 00 Parameter 3 CRC (Optional) ClearAll = 00 01 4 bits 32 × 0 bits 32 bits CRC_u = 96ADh 16 bits 6 bits 2 bits Table 7-33. SOF Tag Response Error Flags Start of Frame 3 .. 10-bit period Present on error only 4-bit – dual pattern code 35 4681C–RFID–09/05 8. Absolute Maximum Ratings Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Parameters Symbol Value Unit Maximum DC current into Coil 1/Coil 2 Maximum AC current into Coil 1/Coil 2 f = 125 kHz Power dissipation (dice) (free-air condition, time of application: 1 s) Electrostatic discharge maximum to MIL–Standard 883 C method 3015 Operating ambient temperature range Storage temperature range (data retention reduced) Icoil Icoil p Ptot Vmax Tamb Tstg 20 20 100 2000 –40 to +85 –40 to +150 mA mA mW V °C °C 9. Electrical Characteristics Tamb = +25°C; fcoil = 125 kHz; unless otherwise specified No. Parameters Test Conditions Symbol Min. Typ. Max. Unit Type* 1 2.1 2.2 2.3 3.1 3.2 3.3 4 5 6.1 6.2 6.3 Notes: RF frequency range Supply current (without current consumed Read – full temperature by the external LC tank range circuit) Program EEPROM POR threshold (50 mV hysteresis) Coil voltage (AC supply) Read, Select, Login command(2) Write/program EEPROM(2) Start-up time Clamp voltage Vcoil pp = 6 V 10 mA current into Coil 1/Coil 2 Vcoilpp = 6 V on test circuit generator and modulation ON(4) Thermal stability Tamb = 25°C(3) (see Figure 9-1 on page 37) fRF IDD 100 125 3 4 25 250 5 7 40 4.0 Vclamp Vclamp kHz µA µA µA V V V ms V V µA mV/°C T Q Q Q Q Q Q T Q T T Q Vcoil pp 3.2 6 6 3.6 tstartup Vclamp Vclamp/Tamb Vmod pp Imod pp Vmod/Tamb 400 7 2.5 –7.5 4.2 600 –4.5 3 16 4.8 Modulation parameters *) Type means: T: directly or indirectly tested during production; Q: guaranteed based on initial product qualification data 1. EEPROM device performance can be influenced by subsequent customer assembly processes especially if subjected to high temperatures or mechanical stress conditions. So Atmel confirms these parameters only for devices as they leave the Atmel production, as undiced wafers or diced wafers in tray, etc. 2. Current into Coil 1/Coil 2 is limited to 10 mA. The damping characteristics are defined by the internally limited supply voltage (= minimum AC coil voltage). 3. IDD measurement setup R = 100 kΩ; VCLK = Vcoil = 5 V: EEPROM programmed to 00 ... 000 (erase all); NRZ, public mode. IDD = (VOUTmax – VCLK)/R 4. Vmod measurement setup: R = 2.3 kΩ; VCLK = 3 V; setup with modulation enabled (see Figure 9-1 on page 37). 5. The tolerance of the on-chip resonance capacitor is ±10% at 3s over whole production. The capacitor tolerance is ±3% at 3σ on a wafer basis. 36 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] 9. Electrical Characteristics (Continued) Tamb = +25°C; fcoil = 125 kHz; unless otherwise specified No. Parameters Test Conditions Symbol Min. Typ. Max. Unit Type* 7 8 9.1 9.2 9.3 10 Notes: Programming time Endurance Data retention Resonance capacitor From last command gap to SOF pattern (36 + 648 internal clocks) Erase all/Write all (1) Top = 55° C (1) (1) Tprog ncycle tretention tretention tretention Cr 70 5 100000 10 96 24 78 5.7 6 ms Cycles T Q T Q T 20 50 Years hrs hrs Top = 150° C Top = 250° C (1) Mask option(5) 86 pF *) Type means: T: directly or indirectly tested during production; Q: guaranteed based on initial product qualification data 1. EEPROM device performance can be influenced by subsequent customer assembly processes especially if subjected to high temperatures or mechanical stress conditions. So Atmel confirms these parameters only for devices as they leave the Atmel production, as undiced wafers or diced wafers in tray, etc. 2. Current into Coil 1/Coil 2 is limited to 10 mA. The damping characteristics are defined by the internally limited supply voltage (= minimum AC coil voltage). 3. IDD measurement setup R = 100 kΩ; VCLK = Vcoil = 5 V: EEPROM programmed to 00 ... 000 (erase all); NRZ, public mode. IDD = (VOUTmax – VCLK)/R 4. Vmod measurement setup: R = 2.3 kΩ; VCLK = 3 V; setup with modulation enabled (see Figure 9-1 on page 37). 5. The tolerance of the on-chip resonance capacitor is ±10% at 3s over whole production. The capacitor tolerance is ±3% at 3σ on a wafer basis. Figure 9-1. Measurement Setup for Vmod R BAT68 750 Coil 1 + 750 V CLK BAT68 ATA5558 Coil 2 Substrate 37 4681C–RFID–09/05 10. Ordering Information(1) ATA5558 ab Mc c - x x x Package - DDW - DDT Drawing - Dice on wafer, 6” un-sawn wafer, thickness 300 µm - Dice in Tray (waffle pack), thickness 300 µm (-PAE (-PP Customer ID(2) M01 11 12 14 (15 Notes: - NOA-2 Micromodule - Plastic Transponder planned) planned) See Figure 10-2 on page 40 See Figure 10-3 on page 41 - Atmel standard (corresponds to 00) - Customer X unique ID code(1) - 2 pads without on-chip C - 2 pads with on-chip 80 pF - 2 pads with on-chip 210 pF - Micromodule with 330 pF See Figure 10-1 on page 39 See Figure 10-1 on page 39 See Figure 10-1 on page 39 See Figure 10-1 on page 39 planned) 1. For available order codes refer to Atmel Sales/Marketing 2. Unique customer ID code programming according to Figure 2-3 on page 4 is linked to a minimum order quantity of 1 Mio parts per year 10.1 Delivery Pre-configuration The ATA5558 is delivered in a pre-programmed state. The traceability blocks (59-61) contain unique non erasable traceability data as described in section “Traceability Data” on page 5. The remaining memory contains erasable demonstration data which can be replaced by customer data after having been cleared using a sequence of Select, ArmClear and ClearAll commands. the demonstration data represents the following device configuration: Block 63 contains configuration data representing Public Mode, FDX-B Modulation, a data rate of RF/32, a Tag ID length of 64 bits, preamble value of 7 and a maximum public mode block value (Maxblock) of 3. Blocks 0-3 contain an FDX-B encoded animal ID code in accordance with ISO 11784 representing a National ID code 000123456789 and country code 999. The Tag ID blocks 56-57 contain a direct copy of the unique traceability data held in blocks 59-60 thus each delivered device will have it’s own 64 bit unique Tag ID code with which anticollision arbitration can be demonstrated. All other blocks are erased. 10.2 Ordering Examples (Recommended) ATA555811 - Tested dice on unsawn 6” wafer, thickness 300 µm, no on-chip capacitor, no damping during POR initialization. 38 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] 10.3 Package Information Figure 10-1. 2 Pad Layout for Wire Bonding Dimensions in µm 70 100 1630 1300 C1 186 650 C2 72 274 186 ATA5558 39 4681C–RFID–09/05 Figure 10-2. Micromodule 40 ATA5558 [Preliminary] 4681C–RFID–09/05 ATA5558 [Preliminary] Figure 10-3. Plastic Transponder 41 4681C–RFID–09/05 A tmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 1150 East Cheyenne Mtn. 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